The invention relates to a liquid pipetting device for delivery of very small quantities of liquid in a multiple well format with a high degree of repeatability and accuracy. Pipetting operations have many and varied applications in medicine and industry. For example, pipetting operations are used in various medical and chemical testing and analyzing procedures where the ability to pipette accurately with a device which has multiple channels would be highly beneficial. If this device could be lightweight and be mounted to a device such as described in the co-assigned U.S. Pat. Nos. 5,055,263 and 5,3067,510 entitled AUTOMATED PIPETTING SYSTEM (hereinafter the "Meltzer Robot"), the benefit would be even more apparent.
The multiple channel pipetting device of this invention has as one of its objects to pipette varying volumes of liquid into multiple wells and, if using disposable pipette tips, to automatically eject those tips when desired by the user. If all the tips fail to eject a signal will be emitted by a sensor, such as an optical interrupt switch, triggering an alarm, such as a warning message displayed on a computer screen, that all the tips have not been ejected by the multiple channel pipetting device.
Current state of the art pipetting devices frequently use long tubing and many fittings which malfunction and are hard to change. For example, leaky connections, defective tubing, and stripped fittings may all cause malfunctioning. Long tubing lengths can adversely affect the accuracy of pipetting.